Using Encryption

Decrypting files

The correct password is required before WinZip® can unzip an encrypted file from a WinZip file. If WinZip does not already know the correct password from a previous operation during the same session on the same archive, it will ask you for the password when it is needed.

Note that WinZip unzips files not only for the Unzip/Extract operation but also when you view or open a file and when you use features such as Test, Unzip and Try, and Install. To enhance the security of your encrypted Zip files, when WinZip is done with the temporarily unzipped files, it will wipe the files prior to deleting them. This will prevent any unauthorized people from being able to recover these temporary files.

Encrypting files

You can encrypt files while they are being added, or you can encrypt (or re-encrypt) all files already in a Zip file (.zip or .zipx).

Encrypting files while adding

The most efficient way to encrypt files is to do so while you are adding them to an archive. To encrypt files while they are being added when using the Legacy toolbar interface in Windows XP, simply check the Encrypt added files check box in the Add dialog. In the WinZip Ribbon interface (in Windows Vista and later), click the Encrypt icon on the Create/Share or Edit tabs OR turn on the Encrypt option in the Actions pane of the main window BEFORE adding files to the Zip file. WinZip will then display the Encrypt dialog during the Add operation, where you will specify the password and encryption method.

When you add files to a Zip file from Windows Explorer, you will have an option to encrypt the files if the Add dialog is displayed. In some cases, however (e.g., when you choose Add to recently used Zip file), there is no Add dialog and therefore no opportunity to encrypt the files while they are being added. In these cases, you can encrypt files after they have been added, as described in the next section.

Encrypting files already in a Zip file

To encrypt files already in a Zip file:

if using the WinZip Ribbon interface, you can encrypt the existing files in a couple of different ways:

Open the Zip file, select the files that you want to encrypt or select all of them, open the Tools tab, and click Selected Files to open the Convert Selected Files dialog where you can choose to encrypt the selected files.

WinZip will display the Encrypt dialog asking for the password to use to encrypt the selected files and then encrypt ONLY the selected files.

Open the Zip file, in the Actions pane on the right, toggle on the Encrypt option in the Convert & Protect section, which will enable the Options button at the bottom of the section, click the Options button and select Apply to all files in the Zip.

WinZip will ask for a password and then encrypt all files currently in the Zip file.

if using the Legacy Toolbar interface, open the Zip file and choose Encrypt from the Actions menu.

WinZip will ask for a password and encryption method and then encrypt all files currently in the Zip file.

in My Computer or Windows Explorer, right click on the Zip file and choose Encrypt from the WinZip shortcut menu.

WinZip will ask for a password and encryption method and then encrypt all files currently in the Zip file.

If a file in the Zip file is already encrypted, it will first be decrypted and then re-encrypted using the method and password you specified. WinZip will first try to decrypt the file using the current encryption password; if the file cannot be decrypted with this password, WinZip will ask you for the correct decryption password. If you are unable to supply the correct password, the file will be skipped, and it will remain unchanged in the Zip file.

Note that it is more efficient to encrypt files while they are being added to the Zip file than to encrypt them after they are already in the Zip file.

Notes on using encryption

The main WinZip window marks encrypted files with an asterisk following the file name or a lock icon in the Encrypted column. The Encrypted column indicates whether a file is encrypted or not and once the correct passphrase has been entered, indicates that the encrypted files are unlocked and accessible.

In the Encrypt and Decrypt dialogs, check the Hide the password check box to prevent the password from being displayed as you type it. If you check this option, the Encrypt dialog will require you to type the password twice for confirmation (to avoid typographical errors).

The quality of the passwords you choose can greatly affect the security of your encrypted documents. Please read about passwords.

Be sure to keep track of your passwords! You will not be able to extract or open any files for which you do not have the correct password.